The present disclosure generally relates to a device for the dosed dispensing of a fluidic medium and, in particular, relates to the dosed dispensing of a fluidic therapeutic and/or diagnostic agent, for example a dosed dispensing of insulin.
Such medication devices, methods and uses can be employed in many areas of the natural sciences, technology and medical engineering. One known device basically works on the principle of a reservoir for receiving a fluidic medium in which a plunger is mounted. This plunger may for example be electrically driven. Many insulin pumps that are on the market operate on this principle. Another known concept works with spring-mounted pressure accumulators, which can be manually filled by a user.
However, these known concepts present a number of technical challenges. For instance, with driven plungers, propulsion of the plunger is needed. This has the effect that pressure builds up in the fluidic medium and a fluid transfer takes place. In addition, this may involve hysteresis effects which may have an influence on the dosing accuracy. This technical challenge is made even more challenging by the fact that when dosing medicaments such as insulin for example, it is necessary to keep a highly accurate check on the dispensed amount in widely differing ranges. On the one hand, a highly accurate dosing is required at low dosage rates, in order for example to keep a check on a base load (basal rate). On the other hand, however, larger dosages must also be dispensed with high precision at short notice, in order to be able to ensure a peak load (bolus). If hysteresis effects or other static frictional effects occur, this may lead to considerable problems in terms of the dosing accuracy. A further challenge is that propulsion generally takes place by an electric drive, meaning that a correspondingly dimensioned power supply is required, for example a battery. This power supply has the effect that known medication devices generally have to be designed with a comparatively large volume.
A further technical challenge is that, before the device is put into operation, and virtually every time it is refilled, venting is generally required. For example, in a typical system, cartridges are exchanged, so venting (priming) of the entire fluidic system is generally required. Together with other technical challenges, this has the overall effect that a user generally has to perform many steps making the handling of the system much more difficult.
Therefore, there is a need to provide a device and method for the dosed dispensing of a fluidic medium which avoids the disadvantages of known devices and methods. In particular, there is a need to improve the ease of handling of the system, to reduce the volume and weight of the device and to increase the dosing accuracy especially for small dosages.